Supercharger for internal-combustion engines



- 1,633,143 June 21 1927' 5, M. UDALE SUPERCHARGER FOR INTERNAL GOMBUSTION ENGINES Filed Aug. 1, 1925 Ul 'n i Il """J l lI Il I i I. l E

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Patented June 21, 1927.

STANLEY M. UDALE, OF DETROIT, MICHIGAN.

SUPERCHIARGER FOR INTERNAL-COMBUSTION ENGINES.

Application led August 1, 1925, Serial No. 47,455.

This invention relates to an improved method of increasing the horsepower of engines at high speed by automatically compensating for the wire drawing of the mix-r ture. The object of this invention is to avoid the necessity of using an air pump having a capacity equal to that of the piston displacement in order to maintain the pressure in the intake manifold at high speeds. If more air is required for the engine than is automatically drawn in bythe piston at high speed it should be possible to provide an air pump having a capacity of ,JU of the piston displacement and thus give a supercharge ofl10%, or rather restore the pressure to full atmospheric pressure. So far all air pumps have been designed to take the whole quantity of the air going to the engine and compress it the necessary degree in order to get the required amount of supercharge. Such air compressors are too expensive for ordinary cars, trucks, tractors, etc.

The figure shows diagramlnatically the application of my invention and comprises the relatively small air pump A driven by the belt B, which may conveniently be the same belt which drives the cooling fan for the engine radiator. The passage C connects the housing of the pump A to the mixing chamber D, which is made in the usual Venturi form. A rich mixture tube E supplies the combustible fluid, together with about 10% of the air, and discharges into the mixing chamber D. An automatic valve F provides the additional air required to give an explosive mixture and maintains a certain necessary minimum depression in D. G is the float chamber supplying fuel to the nozzle H, which discharges into the rich mixture passage E.

The rich mixture passage E is preferably jacketed as shown at F, the heating fluid being preferably the exhaust gases ofthe engine. For convenience the rich mixture passage E is arranged in heat conducting relationship with the exhaust manifold. For the sake of clearness the exhaust manifold, however, is not shown. The balancing pas/- sage H connects the compressed air passage C with the float chamber G. The vent plug J connects the float chamber G with the atmosphere, thus relieving the pressure created by the pump A. The'mixture chamber D communicates with the inlet manifold L M, the communication being controlled by the butterfly throttle K in a well known manner.

Operation-When the engine is running at normal speeds the atomizing air. is drawn up the passage E and fuel is aspirated therevheated rich mixture discharges intothe throat of the Venturi tube D Where it is diluted with the auxiliary air which is drawn past the air valve F. The explosive mixture thus formed in B is drawn past the valve K into the inlet manifold L M.

As the speed of the engine increases a considerable depression is created in the throat of the Venturi tube D, this depression being transferred to the nozzle H causes a correspending increased flow of fuel from the nozzle H. The mixture ratio is thereby maintained substantially constant. However, as this speed increases the fan A com mences to Iset up an appreciable pressure in the passage C which discharges into the throat of the mixing chamber D, reduces the depression therein, and thus tends to check the flow of fuel from the nozzle H into the passage G. The action, therefore, of the pump A is to increase the amount of air drawn into the engine by reducing the depression in the throat of the venturi D. To prevent the mixture becoming unduly lean the pressure within the float chamber G is increased automatically. This automatic increase may be obtained most simply by connecting the float chamber Gr with the air passage C. The tube H Will serve for this communication and need not be of any considerable size.

' In order to regulate the effect of the pres- I sure in C and prevent an undue discharge of fuel from the nozzle H, the size of the vent plug J is regulated. In other words, when less fuel is required a larger vent plug is provided at J, and when more fuel is required a smaller vent plug is substituted for J. By this means it is possible to arrange that as the air pump A becomes more and more effective and more air is discharged from G into D, more fuel will be discharged from H into E to compensate for the effect of the air pump A in increasing the amount of air consumed by the engine.

By arrangingl the passage C so that it discharges into t e throat of the venturi along the axis thereof an njectorefeet 1e,

obtained` so that more air is brought into the engine and the valve lF is not closed by the pressure in the pipe C, as would be the case if the pipe C merely communicated with the space between the mixing chamber D and the atmosphere. 'Ihis latter point is not so'important when no air valve is used. Obviously this invention is not limited in its application to carbureters having air valves, and is even more adapted to carbureters of the so called plain tube variety.,

'Ihe practical advantage of this arrangement is due to the fact that most engines can develop more power at high speed by increasing the compression without knocking, whereas if the attempt is made to increase this power at loW speed by supercharging the engine will knock, because all engines are designed with the highest compression possible without knocking when running with wide open throttle at relatively low engine speed. 'Ihe characteristic of a centrifugal air pump is such that it does not become eective until it approaches the -speed for which it is designed to function.

at I claim is l. In combination with an internal combustion engine, a mixing chamber having an 'air entrance and a Venturi tube, a mixture outlet, a' throttle valve therein, a constant level fuel supply chamber discharging into said Venturi tube and connected to a fuel nozzle, an additional air supply passage discharging into the throat of the Venturi tube and communicating with an engine uoperated supercharger, a communication between said chamber and said supercharger, whereby as the throttle is opened and the engine speed increases an increased fuel and air supply is automatically available, and the mean effective pressure of the engine is maintained at high engine speeds.

2. In combination. with an internal combustion engine, a mixing chamber having an air ent-rance and a Venturi tube, a mixture outlet, a throttle valve therein, a constant level fuel supply chamber discharging into said Venturi tube and connected to a fuel nozzle, an additional air supply passage discharging into the throat of the-Venturi tube and communicating with an engine operated supercharger, a variable vent plug in said constant fuel supply chamber, a communication betweensaid chamber and sald supercharger, whereby as the throt- 

